Abi‐Jaoudeh, Nadine

Abstract Background X‐ray Induced Acoustic Computed Tomography (XACT) is an emerging imaging technique that provides 3D volumetric images from a single projection by detecting X‐ray‐induced acoustic (XA) waves with ultrasound (US) transducers. Unlike MRI or CT, XACT enables real‐time 3D imaging without long acquisition times, 2D limitations, or motion artifacts from mechanical rotation. Furthermore, when integrated with conventional pulse‐echo US through time‐sequenced operation, XACT provides complementary soft‐tissue contrast, establishing it as a promising platform for dynamic interventional radiology (IR) guidance. Purpose This study aims to evaluate the feasibility of XACT as a novel imaging tool for IR, specifically for guiding needle placement and monitoring contrast agent dynamics. Methods We developed a 3D XACT imaging system equipped with a 256‐element 2D matrix array and a portable X‐ray tube to visualize needle insertion and contrast agent dynamics. To capture both needle position and soft tissue anatomy, we integrated a dual‐modality system combining XACT with pulse‐echo US using a 128‐element linear US array. Experiments were conducted on both tissue‐mimic phantoms and soft tissue samples. GPU‐accelerated algorithm has been developed for 3D XACT image reconstruction. Results The results demonstrate the 3D capabilities of XACT imaging for interventional procedures, including monitoring of needle placement and tracking of contrast agent dynamics. The imaging speed reached up to 3∼4 s per frame, constrained by the repetition rate of the X‐ray source and signal to noise ratio. The dual‐modality approach provided clear visualization of the needle's position and the surrounding soft tissue structures, achieving imaging resolution around 2 mm. Conclusions This study demonstrates that XACT imaging is feasible to be used for IR. Its 3D imaging capability with faster imaging speed would be an alternative to cone beam CT and its capability to combine US imaging will provide richer information for soft tissue

Y-90 Selective Internal Radiotherapy (SIRT) is an ablative therapy used for inoperable liver metastasis. The purpose of this investigation was to examine the impact of local control after SIRT on overall survival (OS) in oligometastatic patients. A retrospective, single-institution study identified oligometastatic patients with ≤5 non-intracranial metastases receiving unilateral or bilateral lobar Y-90 SIRT from 2009 to 2021. The primary endpoint was OS defined from Y-90 SIRT completion to the date of death or last follow-up. Local failure was classified as a progressive disease at the target lesion(s) by RECIST v1.1 criteria starting at 3 months after SIRT. With a median follow-up of 15.7 months, 33 patients were identified who had a total of 79 oligometastatic lesions treated with SIRT, with the majority histology of colorectal adenocarcinoma (n = 22). In total, 94% of patients completed the Y-90 lobectomy. Of the 79 individual lesions treated, 22 (27.8%) failed. Thirteen patients received salvage liver-directed therapy following intrahepatic failure; ten received repeat SIRT. Median OS (mOS) was 20.1 months, and 12-month OS was 68.2%. Intralesional failure was associated with worse 1 y OS (52.3% vs. 86.2%, p = 0.004). These results suggest that intralesional failure following Y-90 may be associated with inferior OS, emphasizing the importance of disease control in low-metastatic-burden patients.

Cholangiocarcinoma (CCA) is a heterogenous group of malignancies originating in the biliary tree, and associated with poor prognosis. Until recently, treatment options have been limited to surgical resection, liver-directed therapies, and chemotherapy. Identification of actionable genomic alterations with biomarker testing has revolutionized the treatment paradigm for these patients. However, several challenges exist to the seamless adoption of precision medicine in patients with CCA, relating to a lack of awareness of the importance of biomarker testing, hurdles in tissue acquisition, and ineffective collaboration among the multidisciplinary team (MDT). To identify gaps in standard practices and define best practices, multidisciplinary hepatobiliary teams from the University of California (UC) Davis and UC Irvine were convened; discussions of the meeting, including optimal approaches to tissue acquisition for diagnosis and biomarker testing, communication among academic and community healthcare teams, and physician education regarding biomarker testing, are summarized in this review.